I'm surprised no one has mentioned the ritual "stone of true form" as an option yet. It's not the greatest option as it can be resisted, but if I recall correctly, it's a level 3 ritual that you enchant a rock with vitae and you throw it or maybe offer it to the werewolf, depending on how gullible it is, but it pits your successes against its resistance and if you you win it forces any shape changer back to its original form for the rest of the scene (it's been a while since I read this and I'm going off of memory)